Volume 477, Number 3, January III 2008
|Page(s)||877 - 883|
|Section||Stellar structure and evolution|
|Published online||13 August 2007|
Observatório Nacional-MCT, Rua José Cristino 77, CEP 20921-400 São Cristóvão, Rio de Janeiro-RJ, Brazil e-mail: [claudio;wagner;araujo]@on.br
2 Departamento de Física, UERJ, Rua S. Francisco Xavier 400, CEP 12322-100 Rio de Janeiro-RJ, Brazil
Accepted: 15 July 2007
Aims.We investigate the spectra and the evolutionary stages of two peculiar emission-line stars: RJHA 49 and SS73 21.
Methods.We used low and high resolution optical data. Line identifications and measurements were performed for several features in their spectra.
Results.For each object, we derived the extinction and the excitation temperature from a set of [Fe ii] lines and the electron density from [N ii] lines. For RJHA 49, no detailed spectroscopic study has been done so far. Our low resolution spectrum have confirmed the main characteristics found in previous works on SS73 21. On the other hand, from our high resolution data, we find that the Hα line presents a double peak, in contrast with the suggestion in the literature that it should reveal a P-Cygni profile. Surprisingly, we found a few He i transitions resembling P-Cygni profiles (e.g. He i ), directly suggesting that mass loss is active in SS73 21. We also discuss the nature of these two objects based on data obtained. Although the evolutionary status of SS73 21 seems well established from previous studies (a proto-planetary nebula), the situation for RJHA 49 is not very clear mainly due to its unknown distance. However, from the strength of [N ii] relative to [O i] , the possibility of RJHA 49 being a LBV object is reduced, and a B[e]-supergiant or a proto-planetary nebula status is more plausible.
Key words: stars: emission-line, Be
Based on observations made with the 1.52 m telescope at the European Southern Observatory (La Silla, Chile) under the agreement with the Observatório Nacional, Brazil.
© ESO, 2008
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